• 한국게임학회 논문지
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• 제2권2호
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• pp.28-36
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• 2002

일반적으로 삼각형 메쉬는 가상 게임 캐릭터와 같은 기하학적 객체를 모델링하기 위해 사용되고 있다. 아주 조밀한 메쉬는 복잡한 객체를 세부적으로 표현하는 장점은 있지만 객체를 저장, 전송 및 렌더링하는데 많은 비용을 요구한다. 그러므로 세밀한 객체를 질 좋게 근사시킬 수 있는 기법, 즉 삼각형 메쉬의 단순화가 연구되어왔다. 본 논문에서는 주어진 메쉬를 단순화하기 위해 사용될 수 있는 정점과 에지에 관한 근사 평균 곡률이라는 새로운 측정치를 제시한다. 에지 평균 곡률은 이웃한 에지를 고려하게 계산되고 정점 평균 곡률은 부속된 에지의 평균 곡률의 평균으로 정의된다. 그리고 제안된 측정치를 토끼, 용 및 치아와 같은 모델에 적용한다. 결과로, 제안된 평균 곡률이 주어진 모델에 더 좋은 근사를 제공하기 위한 좋은 기준치로 사용될 수 있음을 알았다.

• 디지털콘텐츠학회 논문지
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• 제10권3호
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• pp.423-431
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• 2009

영상을 검색하는 데에는 형태, 색상, 질감 등 여러 가지 특징을 사용 할 수 있다. 그 중 가장 활발한 연구가 이루어지고 있는 분야가 형태 정보와 색상 정보를 이용하는 분야이다. 형태 정보를 이용하는 검색 방법에는 2D 모멘트와 푸리에변환 등의 방법이 유명하다. 또 다른 방법으로는 CSS(Curvature Scale Space)가 있는데, 이는 윤곽선 정보를 이용하여 윤곽선의 굴곡을 2D 그래프로 표현하여 그 그래프의 극대점을 특징 값으로 사용하여 영상을 비교 검색하는 방법이다. 기존 CSS 방법에는 몇 가지 문제점이 있어서 본 논문에서는 기존 방법을 향상시킨 ICSS 방법을 사용하여 영상을 검색한다. 색상 정보를 이용하는 방법에는 RGB 색상정보를 이용하는 방법과 HSI 색상정보를 이용하는 방법 등이 있는데 본 논문에서는 HSI 색상정보를 이용하여 색상 히스토그램으로 표현한 후 영상의 비교 척도로 사용하였다. 영상의 유사도를 측정하는 방법으로는 유클리디언 디스턴스를 주로 사용하는데, 본 논문에서는 정확도와 검색 시간을 단축시키고자 DTW를 사용하여 영상의 유사도를 측정하였고, 유클리디언 디스턴스를 사용했을 때와 비교하여 성능 향상 결과를 보인다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2961-2966
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• 2007

When the pressure at the weak spot established at a certain part of a high pressure vessel or piping system exceeds a design pressure, this weak spot is burst, and the pressurized gas emitted through the weak spot will cause a compression wave system. In this connection, in the present study, an experimental study by using a conventional shock tube facility is performed to estimate the effects of the material of diaphragm, curvature radius and thickness of materials on the valve opening time in diaphragm. Pressure sensor having 500kHz in natural frequency is installed at 35mm downstream of the rupture diaphragm to measure the static pressure history of propagating and being accumulated compression wave. 4 kinds of materials are used as diaphragm that is aluminium, copper, stainless steel and zinc. The diaphragm radii of curvature R are ${\infty}$, 120mm and 60, respectively. And the depth for $90^{\circ}$ groove is 0.04mm. It is found that the smaller the tensile strength and elongation of the rupture diaphragm is, the smaller the radius of curvature of the rupture diaphragm is, and for the same conditions the thinner the thickness of the rupture diaphragm is, the shorter the valve opening time becomes. Also, the tensile strength, elongation and the radius of curvature of the rupture diaphragm for the same conditions are smaller, the maximum pressure rise caused by the coalescences of the compression wave is smaller. Finally the pressure ratio is higher, the valve opening time is shortened and gradient of pressure increment is more steepen.

• 에너지공학
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• 제22권2호
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• pp.105-111
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• 2013

본 연구는 빌트인 냉장고 내부를 가열하여 냉장고의 열손실 특성을 파악하는 역열손실 방법을 이용하여 냉장고의 열손실이 큰 부분이 어느 영역인지를 분석함으로써 이를 개선하는 것에 목적을 두고 있다. 이를 위해서 적외선 열화상 카메라를 이용하여 냉장고 외부 표면 온도를 측정함으로써 열손실을 분석하였으며 이를 통하여 상대적으로 열손실이 큰 부분인 얼음배출구에서의 열손실 개선을 시도하였다. 또한, 이에 관한 열전달 전산해석을 수행하여 열손실 구조를 규명하였으며 적용 가능한 열손실 개선 방안인 모서리 부분의 곡면반경을 증가하여 열손실이 개선되는 특성을 살펴보았다. 본 연구의 결과로 부터 얼음배출구 모서리 부분의 곡면 반경을 30mm로 하면 모서리 부분의 열손실이 최적으로 개선되는 것을 알 수 있었다.

• 척추신경추나의학회지
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• 제6권2호
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• pp.121-132
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• 2011

Objectives : The purpose of this study is to investigate the cervical spine curvature after whiplash injury by traffic accident. Methods : The cervical lateral radiographs of 102 outpatients who visited emergency room in Kyung-Hee university hospital at Gangdong after whiplash injury by road traffic accident were reviewed to measure the cervical spine angle using C1-7, C2-7 Cobb method, Sagittal tangent method, Jochumsen method and the Ishihara index by two oriental medical doctors. For statistics, we used SPSS version 17.0 for windows. Results : Means of cervical angle are $37.63{\pm}11.34^{\circ}$, $12.92{\pm}9.13^{\circ}$, $16.19{\pm}10.62^{\circ}$, $1.78{\pm}3.37$ and $8.51{\pm}9.78$ by C1-C7 Cobb Method, C2-C7 Cobb Method, Sagittal tangent method, Jochumsen method and Ishihara index, respectively. Hypolordosis is most numeral in patients by C1-C7 Cobb Method(n=40; 39.22%), Sagittal tangent method(n=68; 66.67%). And Straight is the most by Jochumsen method(n=54; 52.94%), but Normal is the most by Ishihara index(n=53; 51.96%). And Female has smaller curvature in cervical spine than male significantly by C2-C7 Cobb method and Sagittal tangent method(P<0.05). Conclusions : Whiplash injury tends to make hypolordosis or straight. And female has more vulnerable curvature than male in whiplash injury.

• 한국해양공학회지
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• 제23권4호
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• pp.91-99
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• 2009

Many longitudinally arranged pipes in ships are subject to considerable displacement loads caused by the hull girder bending of ships and/or thermal loads in some special pipes through which fluids with highly abnormal temperatures are conveyed. As these loads may cause failure in the pipes or their supporting structures, loops have been widely adopted as a measure to prevent such failure, with the idea that they can lower the stress level in a pipe by absorbing some portion of these loads. But since such loops have some negative effects, such as causing extra manufacturing cost and occupying extra space, the number and dimensions of the loops need to be minimized. This research developed design formulas for pipe loops, modeling them as a spring element, for which the axial stiffness is calculated based on the beam theory, incorporating the effects of the curvature of loop corners and the flexibility of the straight portion of the pipe. The accuracy of the proposed design formulas was verified by comparing two results respectively obtained by the proposed formulas and MSC/NASTRAN. The paper ends with a sample application of the proposed formulas showing their efficiency.

• Physical Therapy Rehabilitation Science
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• 제11권1호
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• pp.88-96
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• 2022

Objective: Purpose of this study was to compare muscle activity ratio of multifidus to erector spinalis according to various cueing including tactile stimulation to provide an effective strategy to provide verbal and tactile feedback during exercise to provoke multifidus muscle activation. Design: Cross-sectional study. Methods: Participants of this study included 28 healthy adults. Muscle activities of the multifidus and erector spinalis were measured while the participants performed tasks according to the three different methods of verbal cueing and three different tactile stimulation. Surface EMG was used to measure the muscular activity of the muscles during all the tasks. Results: Tactile stimulation to abdomen and lumbar vertebrae showed no significant difference in the muscle activity ratio (p>0.05). However, muscle activity ratio of the multifidus in relation to the erector spinalis was increased when subjects were given verbal instructions to make lumbar curvature with little force and to make lumbar curvature while pulling navel (p<0.05). However, it was decreased when they were provided with verbal instruction to make lumbar curvature with strong force (p<0.05). Conclusions: According to the results, proper verbal instruction was an effective tool to increase the muscular activity of multifidus. This study aimed to find and provide the most appropriate verbal cueing while doing exercises to activate multifidus.

• 한국안광학회지
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• 제17권2호
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• pp.127-133
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• 2012

목적: 각막곡률계를 이용하여 비접촉식으로 안경렌즈의 곡률반경을 측정할 수 있는 방법에 관하여 조사하고자 한다. 방법: 각막곡률계의 전면부에 -9.50 D ~ -11.50 D의 시력검사용 시험렌즈를 부착한 후 안경렌즈를 각막곡률계의 전면부에서 약 25 cm 가량 떨어진 곳에 설치한다. 안경렌즈의 위치를 조금씩 변경시키며 선명한 마이어상을 관찰하여 곡률반경을 측정한 후, 구면계를 이용하여 곡률반경의 보정공식을 만든다. 결과: 전면부에 시험렌즈를 부착한 각막곡률계를 이용하여 곡률반경 측정이 성공적으로 수행되었다. 측정한 곡률반경은 구면계 데이터를 이용하여 보정값으로 변환 되었으며, 보정값을 만드는 직선의 방정식 5가지를 얻었다. 임의의 여러 가지 렌즈들을 전면부에 시험렌즈가 부착된 각막곡률계로 측정한 후 직선의 방정식을 이용하여 계산한 결과 3.5% 미만의 오차로 측정이 가능함을 알았다. 결론: 전면부에 시험렌즈를 부착한 각막곡률계를 이용하여 비접촉식으로 안경렌즈의 곡률반경을 측정하는 것이 가능하며, 그 정확도는 렌즈메져보다 오히려 높은 것으로 나타났다.

• 한국운동역학회지
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• 제30권1호
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• pp.93-101
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• 2020

Objective: The purpose of this study was to differences of foot plantar pressure balance and lung capacity according to cervical posture in adults. Method: The subjects consisted of 33 adults in their 20s and 50s who use M centers in B-gu and H-gu, B-City, and they measured foot plantar pressure balance and lung capacity according to cervical posture (cervical normal curvature posture, cervical flexural posture) in adults. Results: In this study, the difference of foot plantar pressure balance according to cervical posture were analyzed. In the difference between left and right foot pressure balance. It was 1.50% increased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. In the difference between the anterior and posterior foot pressure balance. It was 4.28% increased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. The difference of lung capacity according to cervical posture were analyzed. In the PEF, It was 58.63 l/min decreased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. In the FEV1, It was 0.15 ℓ decreased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. Conclusion: The results of this study suggest that had a positive effect on differences of foot plantar pressure balance and lung capacity at cervical normal curvature posture in adults. In future research, itis believed that research on the elderly who have collapsed the normal curvature posture due to aging, as well as teenagers whose normal curvature posture due to the use of smartphones, will contribute to the balance of foot pressure and improvement of the right cervical habits. In future studies, it is also believed that it will be necessary to measure lung capacity after performing exercise according to the cervical posture, thereby providing sufficient oxygen during exercise to enhance the persistence and efficiency of the movement.

• 한국의류학회지
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• 제14권3호
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• pp.183-195
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• 1990

The author has studied the effect of clothes design to mask the dorsal curvature that is one of the commonest changes in elderly women. Body measurements including the body type and the status of dorsal curvature were perfor-med on 153 women of over 60 years of age, and then a body form to fit to the mean measure-ments was made to evaluate the effects of various designs to it. With 31 pattern designs modified by changing in their slash lines and gathers using darts, the diminishing effect of the rounded back were evaluated by means of sensory test. The results of this study can be summarized as follows: I . Results from the body measurements 1) The mean body type in elderly women was that of obesity. 2) With the advancement of age, the angle to indicate the degree of dorsal curvature as well as the angle to indicate the posture are increased. II . Concerning to the clothes design to diminish the shape of dorsal curvature 1) Among the designs by the position of darts, the basic pattern (Fig. 5-1-(1)) showed the best effect to mask the shape of dorsal curvature. 2) Out of the applied designs of princess lines, that in which the slash line is pointing toward the shoulder point (Fig. 5-2-(1)) seemed to be most effective. 3) What has angled princess line (Fig. 5-3-(1)) had the most diminishing effect among the waist darts and armhole princess lines. 4) Among the V-shaped designs, the slashed at the shoulder point (Fig. 5-4-(1)) had the best effect to lessen the shape of the dorsal cuuature. 5) Wider angle yoke had better effect to the narrow angle one among the designs with straight yoke, and that with downward direction (Fig. 5-5-(1)) showed the best effect. 6) Between straight wide angle yoke and curved yoke, that of curved one with downward direction (Fig. 5-6-(1)) had better effect as far as the masking effect of dorsal curvature is concerned. 7) Gathers around the neck showed better effect to those around the shoulder, and the more amount of gathers (Fig. 5-7-(1)), there was better effect. 8) The design with midline gathers at the level of horizontal slash line of armhole (Fig. 5-8-(1)) showed better effect to that with seperated gathers. 9) In case of design with gathers at the horizontal line of armhole, it showed the better effect with less amount of gathers in midline ones, but with more amount in the side ones. 10) Considering all 7 different designs with better effect in covering the shape of dorsal curvature, it was evident that the design with gathers was far better than the design with application of slash lines.